Whenever the Code Enforcement Officer finds that a use, located within the Wellhead Protection District 2 and which was in existence as of Tuesday, March 29, 2005, poses an actual or potential threat to the safety or quality of the public groundwater supply, the Code Enforcement Officer shall investigate the threat and notify the landowner and refer the matter to the Planning Board for a public hearing. After a public hearing, the Planning Board may order the property owner to grant permission to the Alfred Water District to install groundwater monitoring wells and to conduct testing for groundwater contamination. Installation of monitoring wells, testing and monitoring of groundwater in such cases shall be at the sole cost of the municipality or the Water District, provided that if such testing indicates that the use is found to cause or contribute to reduction of 80% or more of the state primary or secondary drinking water standards at the water district property line, the property owner shall reimburse the municipality or water district for all expenses incurred for such installation, testing and monitoring.